Skip to main content

Posts

Showing posts with the label HTTP Headers

How to Configure Content Security Policy (CSP) Nonces for Google Tag Manager

  You have likely seen the error in your browser console. It’s red, aggressive, and breaks your analytics:   Refused to execute inline script because it violates the following Content Security Policy directive: "script-src 'self'". This puts engineering teams in a difficult bind. Security teams demand a strict Content Security Policy (CSP) to mitigate Cross-Site Scripting (XSS), effectively banning  'unsafe-inline' . Meanwhile, Marketing teams demand Google Tag Manager (GTM) implementation, which relies heavily on inline script injection to function. The solution is not to lower your security standards. The solution is to implement a cryptographic  nonce  (number used once). This guide details exactly how to architect a nonce-based CSP solution for GTM, covering server-side generation, header injection, and the specific GTM configuration required to propagate trust to your marketing scripts. The Root Cause: Why GTM Breaks Under Strict CSP To fix the problem, y...